The predisposition of experimental animals receiving high levels of dietary fat to certain types of chemical-induced cancers now seems well established. However the measure of response evoked by different types of fats appears to be related to factors other than degree of saturation - notably antioxidant content. Likewise the role of dietary cholesterol in ultraviolet light (UVL)-induced skin cancer seems clouded by variations in diet not properly controlled in earlier studies. Although dietary cholesterol involvement in skin cancer was suggested over 40 years ago, recent evidence, although indirect, lends new concern for the involvement of this natural constituent in actinic carcinogenesis. This proposal is designed to (1) evaluate the effect of nutritional stress, i.e., high cholesterol and quantitative and qualitative alterations in dietary fat, upon the incidence of UVL-induced skin cancer and (2) to determine whether dietary antioxidants have a mollifying effect upon potential predisposition to carcinogenesis by dietary lipids.